WO2001068726A1

WO2001068726A1 - Atom transfer radical polymerisation catalyst

Info

Publication number: WO2001068726A1
Application number: PCT/GB2001/001001
Authority: WO
Inventors: Vernon Charles Gibson; Rachael Kerry O'reilly; Warren Reed
Original assignee: Bp Chemicals Limited
Priority date: 2000-03-16
Filing date: 2001-03-08
Publication date: 2001-09-20
Also published as: GB0006389D0; AU6613801A

Abstract

A catalyst composition for the polymerisation or copolymerisation of a radically polymerisable monomer is disclosed, and comprising (i) an initiator having a radically transferable atom or group, and (ii) a compound of the formula LpM[m](Q) or its precursors, wherein each L is independently a neutral or anionic group or ligand; m is the oxidation state of the metal M and p is the number of ligands or groups L present in the compound additional to Q such that the overall charge on the compound is zero; Q is a ligand of the formula (I) or (II) wherein R?1 to R11¿ are each independently selected from hydrogen, halogen, hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl, substituted heterohydrocarbyl or SiR'¿3? where each R' is independently selected from hydrogen, halogen, hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl, substituted heterohydrocarbyl; and M is a metal in formal oxidation state m, selected from Ti[II], Ti[III], Ti[IV], Fe[II], Fe[III], Co[II], Co[III], Ni[II], Cr[II], Cr[III], Mn[II], Mn[III], Mn[IV], Ta[II], Ta[III], Ta[IV], Rh[II], Rh[III], Y[II], Y[III], Sc[II], Sc[III], Ru[II], Ru[III], Ru[IV], Pd[II], Zr[II], Zr[III], Zr[IV], Hf[II], Hf[III], Hf[IV], V[II], V[III], V[IV], Nb[II], Nb[III], Nb[IV], Nb[V], Cu[I], Cu[II], Mo[II], Mo[III], W[II], W[III], Rh[IV], Re[II], Re[III], Co[I], Zn[I], Zn[III], Au[I], Au[II], Ag[I], and Ag[II].

Description

ATOM TRANSFER RADICAL POLYMERISATION CATALYST

The present invention relates to novel catalyst compositions and to the polymerisation of olefinically unsaturated monomers using said catalyst compositions.

A recent development in the control of radical polymerisation systems is atom transfer radical polymerisation (ATRP) based on a redox reaction with a transition metal compound. ATRP is believed to result from two parameters (i) the presence of a low constant concentration of growing radicals and (ii) a fast and reversible equilibrium between the growing radicals and the dormant polymer species. If the concentration of growing radicals is kept low enough and a fast and reversible equilibrium between growing radicals and the dormant polymer species is established the proportion of termination reactions in comparison to propagation can be minimised which results in better predictability of molecular weight and lower polydispersities. A more detailed discussion of the mechanism of ATRP may be found in WO 96/30421. This describes a method for atom or group transfer radical polymerisation of an alkene such as styrene whereby the alkene is polymerised in the presence of an initiator, a transition metal compound and a ligand and the formed polymer is subsequently isolated. The use of an alkyl halide initiator, copper (I) chloride, and bipyridine ligand to produce controlled molecular weight polymers of low polydispersity is described.

However the process described in WO 96/30421 has the disadvantage that it is a heterogeneous system due to the fact that the copper catalyst is only partially soluble in the polymerisation system. Thus it is difficult to determine the level of active catalyst in the polymerisation system, and difficult to predict or control the properties e.g. polydispersity of the final product. Coordination polymerisation heterogeneous catalysts are also well known to be less efficient than homogeneous catalysts in terms of g/g productivity, and also sometimes require specific separation steps from the product in commercial use. As a result, homogeneous systems are generally preferred where possible. WO 97/47661 describes the use of copper diimine complexes which allow homogeneous atom transfer polymerisation of olefinically unsaturated monomers and thus the level of active catalyst in the mixture to be controlled. However rates of conversion for styrene using these complexes are relatively low, and polydispersities (Mw/Mn) relatively high. WO 99/58578 discloses a catalyst composition comprising

(i) an initiator having a radically transferable atom or group, and (ii) a component of the formula [Fe[T] L] . (T/b)X, where Fe is iron and T its oxidation state, X represents an atom or group covalently or ionically bonded to Fe, b is the valency of X, and L is a ligand of the formula R^I-N=CH-(CH₂)_π-CH=N-R² in which R¹ and R² are independently selected from Ci-Cio alkyl, aryl and substituted aryl, and n is 0 or 1.

According to the present invention there is provided a catalyst composition comprising (i) an initiator having a radically transferable atom or group, and a compound of the formula L_pM^{[ ]}(Q) or its precursors, wherein each L is independently a neutral or anionic group or ligand; m is the oxidation state of the metal M and p is the number of ligands or groups L present in the compound additional to Q such that the overall charge on the compound is zero; Q is a ligand of the formula (I) or (II)

Formula (I) Formula (II) wherein R to R are each independently selected from hydrogen, halogen, hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl, substituted heterohydrocarbyl or SiR'₃ where each R' is independently selected from hydrogen, halogen, hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl, substituted heterohydrocarbyl; and M is a metal in formal oxidation state m, selected from Ti[II], Ti[III], Ti[IV], Fe[II], Fe[III], Co[II], Co[III], Ni[II], Cr[II], Cr[III], Mn[II], Mn[III], Mn[IV], Ta[II], Ta[III], Ta[IV], Rh[II], R flll], Y[II], Y[III], Sc[II], Sc[III], Ru[II], Ru[III], Ru[IN], Pd[II], Zr[II], Zr[III], Zr[IV], Hf[II], Hf[III], HfTIV], V[II], V[III], V[IV], Νb[II], Nb[III], Nb[IV], Nb[V]; Cu[I], Cu[II], Mo[II], Mo[III], W[II], W[III], Rh[IV], Re[II], Refill], Co{Tj, Zn η, ZnrHT], Au[I], Au[II], Ag[I], and Ag[II].

Examples of L include halide, acetate, acetyl acetonate, alkyl, heteroalkyl, allyl, phosphate, an olefin, carbon monoxide, a phosphine, an amine, a solvent molecule such as water, diethyl ether, acetone, acetonitrile, and the like. Other examples of L are BF₄ ^", SbF₆ ^", PF₆ ^", triflate, aryl or alkyl borate, sulfate, phosphate and the like. In the formula of compound (ii) p may take any value consistent with the co-ordination requirements of the metal. When p is greater than 1 it will be understood that the corresponding multiple L species present in the compound may be the same or different. Particularly suitable examples of L include chloride and bromide.

In some embodiments two or more L ligands may be linked together to form bidentate or multidentate ligands.

By precursors of the compound of the formula L_pM^[m](Q) it is understood that the catalyst may comprise a mixture of ligands L and Q together with a metal salt, these forming the above compound in situ. The catalyst composition may also comprise more than one compound covered by definition (ii). The complex described by the above compound (ii) may be supported on an inorganic or organic solid support.

The initiator suitable for use in the present invention may be any initiator having a radically transferable atom or group. Examples of suitable initiators include conventional atom transfer radical addition initiators, for example, organic halides, such as alkyl halides, e.g. alkyl chlorides or bromides such as CC1₄, CHC1 and CCl₃Br, activated alkyl halides e.g. alkyl halides containing at least one alpha-electron withdrawing group such as an ester, e.g. 2-bromoethylisobutyrate or a ketone, e.g. 2- bromoisobutyrophenone or an optionally substituted aryl e.g. phenyl or nitro-substituted phenyl. Other suitable initiators include arenesulphonyl halides, particularly chlorides, which can be substituted or unsubstituted such as para-toluenesulphonyl chloride and para-methoxybenzenesulphonyl chloride. Preferred initiators include CC1₄ and para- toluenesulphonyl chloride, also phenoxybenzene-4,4'-disulphonyl halides such as phenoxybenzene-4,4'-disulphonyl chloride.

It will be understood that such initiators may also be molecules (monomeric or polymeric) which contain more than one radically transferable atom or group. Examples of monomeric multifunctional initiators include alkyl dihalides and sulphonyl halides such as 1,3-benzene disulphonyl chloride. Suitable initiators for the invention also include polymers, which may optionally be based on styrene, which contain one or more radically transferable group present at the chain ends and/or pendent to the main chain and distributed along its length. As described in WO 98/01480, for example, such initiator molecules may also contain within them other functional groups which are not active to radical polymerisation but which can be used to initiate anionic or cationic living polymerisation of other monomers. In this way a variety of block copolymer architectures can be accessed. It will be understood that such multifunctional initiators provide access to a wide range of star branched and grafted homopolymer and copolymer architectures with the consequent enhanced potential to fine-tune properties. The use of mixed initiators is also within the scope of the invention.

It is possible to conduct the polymerisation in reverse ATRP mode where the metal complex controls the activity of radicals generated by conventional radical initiators known to those skilled in the art, such as peroxide and azo functional molecules. In this mode of operation the complex must first exchange a radically transferable atom or group onto polymerising radicals generated by the initiator. In carrying out this function the metal is reduced in oxidation state and therefore must be present initially in the oxidised form of its redox couple. In this mode of operation at least one of L must be selected to provide the radically transferable group, for example halide. In reactions where initiation is performed with a molecule already containing an atom or group which can radically transfer to the metal complex in the initiation step then it will be understood the metal should be present in the reduced form of its redox couple. In this mode of operation it is not necessary for L to be a radically transferable group as this is supplied by the initiator.

In the compound of formula L_pM^{[ ]}(Q), preferred metals are Fe[II], Fe[III], Co[II], Co[III], Cr[II], Cr[III], Mn[II], Mn[III], Mn[IN], V[II], V[III] and V[IN]. In the ligand of Formula (I), R⁵ and R⁷ are preferably independently selected from substituted or unsubstituted alicyclic, heterocyclic or aromatic groups, for example, phenyl, 1-naphthyl, 2-naphthyl, 2-methylphenyl, 2-ethylphenyl, 2,6-diisopropylphenyl, 2,3-diisopropylphenyl, 2,4-diisopropylphenyl, 2,6-di-n-butylphenyl, 2,6- dimethylphenyl, 2,3-dimethylphenyl, 2,4-dimethylphenyl, 2-t-butylphenyl, 2,6- diphenylphenyl, 2,4,6-trimethylphenyl, 2,6-trifluoromethylphenyl, 4-bromo-2,6- dimethylphenyl, 3,5 dichloro2,6-diethylphenyl, and 2,6,bis(2,6-dimethylphenyl)phenyl, cyclohexyl and pyridinyl.

In a preferred embodiment R⁵ is represented by the group "T" and R⁷ is represented by the group "S" as follows:

wherein R¹⁹ to R²⁸ are independently selected from hydrogen, halogen, hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl or substituted heterohydrocarbyl; when any two or more of R¹ to R⁴, R⁶ and R¹⁹ to R²⁸ are hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl or substituted heterohydrocarbyl, said two or more can be linked to form one or more cyclic substituents.

The ring systems T and S are preferably independently 2,6-hydrocarbylphenyl or fused- ring polyaromatic, for example, 1-naphthyl, 2-naphthyl, 1-phenanthrenyl and 8- quinolinyl.

Preferably at least one of R , R , R and R is hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl or substituted heterohydrocarbyl. More preferably at least one of R¹⁹ and R²⁰, and at least one of R²¹ and R²², is hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl or substituted heterohydrocarbyl. Most preferably R , R , R and R ^" are all independently selected from hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl or substituted heterohydrocarbyl. R¹⁹, R²⁰, R²¹ and R²² are preferably independently selected from methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert- butyl, n-pentyl, neopentyl, n-hexyl, 4-methylpentyl, n-octyl, phenyl and benzyl. R¹, R², R³, R⁴, R⁶, R¹⁹, R²⁰, R²¹, R²², R²³, R²⁵, R²⁶ and R²⁸ are preferably independently selected from hydrogen and C] to C₈ hydrocarbyl, for example, methyl, ethyl, n-propyl, n-butyl, t-butyl, n-hexyl, n-octyl, phenyl and benzyl.

In an alternative embodiment R⁵ is a group having the formula -NR²⁹R³⁰ and R⁷ is a group having the formula -NR R , wherein R to R are independently selected from hydrogen, halogen, hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl or substituted heterohydrocarbyl; when any two or more of R to R , R and R to R are hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl or substituted heterohydrocarbyl, said two or more can be linked to form one or more cyclic substituents. Each of the nitrogen atoms is coordinated to the metal by a "dative" bond, ie a bond formed by donation of a lone pair of electrons from the nitrogen atom. The remaining bonds on each of these atoms are covalent bonds formed by electron sharing between the atoms and the organic ligand as shown in the defined formula for the metal complex illustrated above. The present invention further provides a process for the polymerisation and copolymerisation of a radically polymerisable monomer, comprising contacting the monomer under polymerisation conditions with a catalyst composition as defined above. A further aspect of the invention is the use of the above-defined composition as a polymerisation catalyst for radically polymerisable monomers. Monomers suitable for use in the polymerisation process of the present invention include any radically polymerisable monomer. Preferred monomers include ethylene; optionally substituted conjugated dienes such as 1,3-butadiene, isoprene; acids and anhydrides such as acrylic acid or acrylic anhydride; (meth)acrylamides; vinyl halides e.g. vinyl chloride; (meth)acrylonitrile; (meth)acrylate esters of Cι-C₂o alcohols e.g. methyl methacrylate, ethyl methacrylate, propyl methacrylate (all isomers), butyl methacrylate (all isomers); vinyl esters of Cι-C₂₀ alcohols e.g. vinyl acetate, vinyl propionate or vinyl butyrate; vinyl amides such as vinyl pyrrolidone, and other vinyl amides having up to 8 carbon atoms; vinyl ketones such as ethylvinyl ketone, butylvinyl ketone and other vinyl ketones having up to 8 carbon atoms; vinyl substituted aryls e.g. vinyl substituted phenyls, vinyl substituted naphthyls. The aryl ring may be substituted by at least one vinyl group such as 1- 2 vinyl groups. Examples include styrene and 1,4 divinyl benzene. The vinyl group(s) may be substituted or unsubstituted, e.g. substituted styrenes. Suitable vinyl group substituents include a Cι-C₆ alkyl (preferably at the alpha-carbon atom) e.g. methyl. Examples include alpha-methyl styrene. The vinyl substituted aryl may also have at least 1, preferably 1 to 3 substituents on the aryl ring. Thus, phenyl may be substituted by 1 to 3 substituents. Suitable aryl ring substituents e.g. phenyl ring substitutents may be Cι-C₆ alkyl, Cι-C₆ alkenyl, C]-C₆ alkoxy, halogen, carboxy and nitro.

Examples of acrylates include methyl acrylate, ethyl acrylate, butyl acrylate, 2- ethylhexyl acrylate, isobornyl acrylate, and functional derivatives thereof such as 2- hydroxy ethyl acrylate, 2-chloro ethyl acrylate and the like. Such acrylates generally have from 1 to 12 carbons, preferably from 1 to 8 carbons.

Examples of methacrylates are methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate, and functional derivatives thereof such as 2-hydroxy ethyl methacrylate, 2-chloro ethyl methacrylate and the like. Such methacrylates generally have from 1 to 12 carbons, preferably from 1 to 8 carbons.

Examples of (meth)acrylamides include (meth)acrylamide itself, N-methyl (meth)acrylamide, N,N'dimethyl (meth)acrylamide and the like.

Examples of acids and anhydrides include (meth)acrylic acid, maleic acid, maleic anhydride, vinyl sulphonic acid, itaconic acid. Examples of other monomers include amino olefins, vinyl pyridine, N-amino ethyl acrylamide, N-aminoethyl acrylate, isoprene, butadiene, and C -C₈ α-olefins such as ethylene, propylene, 1-butene, isobutene, 1-hexene, 1-octene and the like.

Particularly preferred monomers are styrene, methyl acrylate, methyl methacrylate, vinyl acetate and acrylonitrile. A mixture of two or more monomers may be used. The monomers may also be polymerised with a natural or synthetic rubber or combination thereof, such that the resulting polymeric product comprises a polymer or copolymer of styrene having rubber grafted thereon.

Examples of rubbers include natural rubbers such as 1,4-polyisoprene, with those derived from the Hevea brasiliensis tree and quayule bush being useful. Synthetic rubbers include polybutadiene rubber, polyisoprene rubber, styrene-butadiene rubber, nitrile rubber, neoprene rubber, polysulphide rubber, polyacrylate rubber, epichlorohydrin rubber, fluoroelastomer, chlorosulphonated polyethylene rubber, polyurethane, or a thermoplastic rubber.

With regards to the polymerisation reaction using the catalyst composition herein described, the relative proportions of initiator and metal complex component are those effective to achieve the desired polymer product.

The molar ratio of initiator to monomer is chosen depending on the molecular weight of the product polymer to be achieved. For molecular weights of e.g. polystyrene or polymethyl methacrylate in the range 50k - 1 million the initiator may be present in a molar ratio of from 2 x 10^"3 : 1 to 10^"4 : 1 relative to monomer, for molecular weight range 100k - 600k the initiator is preferably present in a molar ratio of from 10^"3 : 1 to 1.6 x 10^"4 : 1 relative to monomer and to obtain polymer product of molecular weight in the range 250k - 500k, the initiator is preferably present in a molar ratio of from 4 xlO^" : to 2 xlO^"4 :1 relative to monomer.

The molar ratio of initiator to the metal complex component to effect polymerisation can depend upon the degree of solubility of the metal complex component in the reaction system but may be from 10^"4 : 1 to 10:1, preferably from 10^" : 1 to 5: 1, more preferably from 0.3 : 1 to 2: 1 and especially from 0.9 : 1 to 1.1 : 1.

The greater the degree of solubility of the metal complex component the greater the concentration of metal there will be present in the reaction system. Consequently in a homogeneous system the molar proportion of metal component to initiator may be reduced, e.g. 10^"3 : 1.

In reactions where the catalyst complex is prepared in-situ by mixing components it is common to use a stoichiometric excess of ligand to metal salt. The molar ratio of ligand : metal used is then generally between 100: 1 and 1: 1, for example 5: 1 to 1 :1, and sometimes from 3: 1 to 1 : 1.

The polymerisation of the present invention may be carried out in the presence of solvent or absence of solvent. Suitable solvents include protic and non-protic solvents such as water, aromatic hydrocarbon solvents, ethers, cylic ethers, C₅-Cιo alkanes, halogenated hydrocarbon solvents (which do not act as an initiator under the reaction conditions), acetonitrile, propionitrile, dimethylformamide and Cι-C₆ alcohols. Suitable aromatic hydrocarbon solvents include benzene, toluene, xylene (all isomers), and ethylbenzene. Suitable ethers include diethyl ether, dimethoxyethane, diethoxyethane, diphenyl ether, anisole. Suitable cyclic ethers include dioxane and tetrahydrofuran. Suitable C₅-C₁₀ alkanes include hexane, heptane. Suitable halogenated hydrocarbon solvents include dichloromethane, 1,2 dichloroethane. Suitable Cι-C₆ alcohols include methanol, ethanol, propanol. The polymerisation process is suitably carried out at a temperature in the range of from -20°C to 200°C, suitably from 40°C to 150°C , for example from 80°C to 120°C. Alternative suitable temperature ranges are from 40 to 160°C, preferably from 40 to 85°C for emulsion polymerisation, and from 80 to 200°C, preferably 100 to 180°C, for bulk polymerisation. Aqueous suspension polymerisation temperatures are typically from 80 to 150°C. Where polymerisation can be initiated by thermally generated radicals, such as with styrene, it is beneficial to conduct the reaction at as low a temperature as possible to ensure the maximum control over molecular weight and molecular weight distribution by the catalyst complex. Thus it is beneficial to carry out styrene polymerisation below 160°C, more preferably below 130°C, and most preferably at or below 120°C.

The polymerisation process of the present invention may be carried out in the presence of an activator, such as a Lewis acid activator. Typical Lewis acids which may be used include aluminium alkyls, e.g. methyl aluminium bis(2,6 di-tert- butylphenoxide), aluminium alkoxides such as aluminium tris(iso-propoxide), aluminium halides such as aluminium trichloride, alkyl zinc reagents such as diethyl zinc and boranes such as BPh₃ and B(C₆Fs) .

The use of an activator may increase the rate of polymerisation, for example the rate of polymerisation of (meth)acrylate esters of Cι-C₂₀ alcohols e.g. methyl methacrylate , and in particular methyl methacrylate polymerisation in the presence of an aluminium activator.

The molar ratio of activator to metal complex used may be, for example, in the range from 1 : 1 to 10: 1 such as 2: 1 to 6: 1. The polymerisation process may be carried out in bulk, solution, emulsion or suspension (slurry), as a single phase or multiple phases. Gas phase polymerisation can be carried out wherein the monomer in gaseous phase contacts a bed of the catalyst supported on a suitable substrate which has been previously contacted with the initiator(s) and ligand. Bulk polymerisations are particularly advantageous. The invention can be practiced as a batch, semicontinuous, or continuous process. Monomers, initiator, catalyst, and optionally solvent, are mixed together in a suitable reaction vessel. The order of component addition is not critical although it is desirable that monomer is present before others items are introduced. This vessel may be purged with an inert gas, such as nitrogen. The gas purge may be continued throughout reaction. Polymerisation may be carried out with all monomers present at the begining or with monomers added incrementally or continuously throughout the reaction. The reaction mixture may be agitated by any known method to mix components. The reaction is continued until the desired level of polymerisation has occurred, generally from about 40% to about 100% conversion of monomer to polymer. The reaction mixture may then be treated as required in subsequent steps to achieve the final desired product. For example, the reaction may be stopped by cooling, addition of inhibitor such as 4-methoxyphenol and the like, and discontinuing monomer feed. Alternatively, the reaction mixture may be taken on to further work-up stages such as monomer devolatalisation, catalyst removal steps, and/or polymer isolation.

The polymers and copolymers formed by the process of the present invention include straight and branched chain polymers and copolymers, star (co)polymers and the like. The copolymers can be random, alternating, block, graft, multiblock, straight chain, star, star block copolymers and the like. The (co)polymers may also be high impact polystyrene wherein a natural or synthetic rubber or a combination thereof is grafted onto the polymer or copolymer.

The polymers of the invention may also be used in blends with other polymers, or conventionally polymerised versions of the same polymers, to modify their properties for different applications. The polymers and copolymers may be further processed by moulding, spinning, extruding, and the like. Additives include lubricants, dyes, plasticisers, pigments, stabilisers, antistatic agents, antioxidants, fillers and blowing agents. Utilisations for the polymers and copolymers include moulded or foamed articles, sheets, films, pipes, tubings, fibres and the like. EXAMPLES EXAMPLE 1 Synthesis of catalysts

Catalyst 1 : 2,6-di | l-rN-(2-methylphenyl) iminol isobutyl) pyridine iron dichloride This complex was synthesised according to the general procedure described in WO 99/12981.

Catalyst 2 - Synthesis of 2,6-bis-[(2,6-diisopropylphenylimino)methyl]pyridine iron(II) acetylacetonate hexafluoroantimonate

2,6-bis-f(2,6-diisopropylphenylimino)methyllpyridine iron(II chloride hexa- fluoroantimonate acetonitrile adduct: Silver hexafluoroantimonate (1.22g, 2.0mmol) and 2,6-bis-[l-(2,6-diisopropylphenylimino)ethyl]pyridine iron(II) chloride (687 mg, 2.00 mmol) were dissolved in 50ml MeCN. A white precipitate in a dark red solution was formed immediately. After stirring at r.t. overnight the solution was filtered off and the solvent was removed in vacuo. The residue was washed with Et₂O (2x30 ml). After drying in vacuo a red powder was obtained. Yield: 1.59 g (94%). Η-NMR (250 MHZ, CD₂C1₂, r.t., all peaks appear as broad singlets): δ -14.17 (IH, Py-H_P), -13.29 (2Η, Ph-H_p), -8.87 (6Η,

-2.29 (24H, iPr- e), 12.46 (4H, iPr-CH or Ph-H_m), 14.78 (4Η, Ph-H_m or iPr-CHj, 101.45 (2Η, Py-H_m). IR (neat compound): 3064 (w, v (C-Η)AΓ), 2964 (s, v(CΗ₃)_as), 2929 (m, v(CH₃)), 2872 (m, v(CH₃)_s), 1617 (m, v(C=N)), 1581 (s, v(C-C)py), 1460 (m, v(C-C)_Ph or δ(CH₃)_as), 1443 (m, v(C-C)_Ph or δ(CH₃)_as), 1368 (m, δ(CH₃)_s), 1262 (s), 802 (s, δ(C-H)_Ar), 781 (s, δ(C-H)_Ar), 737 (s, δ(C-H)_Ar), 670 (s, v(Sb-F)) cm^"1. FAB-MS (m/e): 572 (100%), 556 (10%).

2,6-bis-f(2,6-diisopropylphenylimino)methyllpyridine iron(II) acetylacetonate hexafluoroantimonate: Silver acetylacetonate (150mg, 0.72mmol) and 2,6-bis-[(2,6-diisopropylphenylimino)methyl]pyridine iron(II) chloride hexafluoroantimonate acetonitrile adduct (540mg, 0.64mmol) were dissolved in 20 ml MeCN. A white precipitate in a dark red solution was formed immediately. After stirring at r.t. overnight, the solution was filtered off and the solvent was removed in vacuo. The red residue was redissolved in 20 ml DCM and precipitated with 60 ml pet. ether. The supernatant solution was filtered off and the residue was washed with pet. ether (2x20 ml) and dried in vacuo and isolated as a red powder. Crystals suitable for X-ray analysis were grown via crystallisation from a concentrated DCM solution layered with pentane. Yield: 340 mg (61 %). Η-NMR (250 MHZ, CD₂C1₂, r.t., all peaks appear as broad singlets): δ -60.71 (6H, N=C- e), -33.12 (IH, O=C-CH or Py-Hp), -22.33 (4Η, Ph-H_m or iPr-CH), -12.70 (2Η, Ph-H_p), -6.02 (12H, iPr- e), -2.85 (12H, iPr- ?), 2.34 (6H, O=C- ?), 13.05 (4H, iPr-CH or Ph-H_m), 30.50 (1Η, Py-Hp or O=C-CH ), 1 17.54 (2Η, Py-H_m). IR (neat compound): 3064 (w, v(C-Η)_Ar), 2967 (m, v (CH₃)_as), 2930 (w, v(CH₃)), 2872 (w, v(CH₃)_s), 1625 (w, v(C=N)), 1588 (m, v(C-C)_Py), 1567 (s, v(C~C) + v(C«O)), 1522 (s, v(C«C) + v(G=O)), 1467 (m, v(C-C)_Ph or δ (CH₃)_as), 1440 (m, v(C-C)_Ph or δ(CH₃)_as), 1369 (s, δ(CH₃)_s), 1261 (m), 816 (w, δ (C-H)_Ar), 795 (w, δ(C-H)_Ar), 776 (m, δ(C-H)_Ar), 758 (w, δ(C-H)_Ar), 742 (w, δ(C-H)_Ar), 659 (s, v(Sb-F)) cm^"1. FAB-MS (m e): 636 (100%), 620 (10%). Anal. Calcd. for C₃₈H₅₀N₃O₂FeSbF₆ x 1 CH₂C1₂: C, 48.93; H, 5.47; N, 4.39. Found: C, 49.1 1; H, 5.33; N, 4.33. μ_efT= 5.0 BM (Evans' method) and 4.8 BM (Evan's balance).

Catalyst 3 : 2,6-diacetylpyridinebis (2,6-diisopropylanil) manganese dichloride

This complex was synthesised according to the general procedure described in WO 99/12981.

Catalyst 4: 2,6-diacetylpyridinebis (2, 4,6-trimethyl anil) chromium dichloride

Catalyst 5: 2,6-diacetylpyridinebis (2,6-diisopropylanil) chromium dichloride

Catalyst 6: 2,6-diacetylpyridinebis (2,6-diisopropylanil) titanium trichloride

Catalyst 7: 2,6-diacetylpyridinebis (2,6-diisopropylanil) iron dichloride

Catalyst 8: 2,6-diacetylpyridinebis (2.6-diisopropylanil) vanadium trichloride

Catalyst 9: 2.6-bis-r{2,6-diisopropylphenylamido)methyl]pyridine iron dichloride

The ligand for Catalyst 9 below was made according to the procedure described by Guerin et al in Organometallics, 1996, 15, 5085-5089. 0.45g of this ligand was then mixed with 0.23 g of FeCl₂(THF)ι. , and suspended in 100 ml of toluene. The reaction mixture was refluxed in toluene for 24 hours. The solution was allowed to cool to room temperature, which resulted in the formation of large dark green crystals of Catalyst 9. The crystals were washed and dried.

EXAMPLE 2 - Polymerisations

The monomer used in each case was styrene (>99%), purchased from Fluka and purified by distillation. The initiators employed were:

1-Phenylethyl bromide (1-PEBr) 1 -Phenylethyl chloride (1-PECl) - prepared according to a literature preparation [J.Org.

Chem., 1980,45,3527] and purified by column chromatography

Phenoxybenzene-4,4'-disulphonyl chloride (PDSC)

All polymerisations were performed under an inert atmosphere. In an ampoule equipped with a magnetic stirrer bar the following were placed in order, monomer, initiator and catalyst in various ratios given in Table 1 and then sealed. In most cases the catalyst was soluble in the monomer solution. The ampoules where heated in an oil bath at

130°C for 5 hours with magnetic stirring. After 5 hours the contents of the ampoules were dissolved in THF. This solution was added dropwise to an approximately 20 fold excess of rapidly stirred acidified methanol (1% cone. HCl). The precipitate that formed was filtered off and washed with methanol. The precipitate was dried for 24 hours in a vacuum oven at 60°C.

The polystyrene samples were analysed using a GPC Gynkotek machine. The samples were dissolved in chloroform (HPLC grade) to give a lmg/ml solution and then 100D1 of this solution was analysed at room temperature.

The results of the polymerisations are shown in Table 1 below:

TABLE 1

Claims

1. Catalyst composition comprising

(i) an initiator having a radically transferable atom or group, and

(ii) a compound of the formula L_pM^[m](Q) or its precursors, wherein each L is independently a neutral or anionic group or ligand; m is the oxidation state of the metal

M and p is the number of ligands or groups L present in the compound additional to Q such that the overall charge on the compound is zero; Q is a ligand of the formula (I) or

(II)

Formula (I) Formula (II) wherein R¹ to R¹¹ are each independently selected from hydrogen, halogen, hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl, substituted heterohydrocarbyl or SiR'₃ where each R' is independently selected from hydrogen, halogen, hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl, substituted heterohydrocarbyl; and M is a metal in formal oxidation state m, selected from Ti[II], Ti[III], TifIN], Fe[II], Fe[III], Co[II], Co[III], Νi[II], Cr[II], Cr[III], Mn[II], Mn[III], Mn[IV], Ta[II], Ta[III], Ta[IV], Rh[II], Rh[IIi], Y[II], Y[III], Sc[II], Sc[III], Ru[II], Ru[III], Ru[IV], Pd[II], Zr[II], Zr[III], Zr[IN], Hf[II], Hf[III], Hf[IN], V[II], V[III], V[IV], Νb[II], Nb[III], Nb[IN], Νb[V]; Cu[I], Cu[II], Mo[II], Mo[III], W[II], W[III], Rh[IV], Re[II], Re[III], Co[I], Zn[I], Zn[III], Au[I], Au[II], Ag[I], and Ag[II].

2. Composition according to claim 1, wherein L comprises halide, acetate, acetyl acetonate, alkyl, heteroalkyl, allyl, phosphate, an olefin, carbon monoxide, a phosphine, an amine, water, diethyl ether, acetone, acetonitrile, BF₄ ^", SbF₆ ^", PF₆ ^", triflate, aryl or alkyl borate, sulfate, or phosphate.

3. Composition according to claim 1 or 2 wherein the initiator comprises an alkyl halide or arenesulphonyl halide.

4. Composition according to claim 3, wherein the initiator comprises CC1₄, CHC1₃, CCl₃Br, 2-bromoethylisobutyrate, 2-bromoisobutyrophenone, para-toluenesulphonyl chloride, 1-phenylethyl bromide, 1-phenylethyl chloride, para- methoxybenzenesulphonyl chloride or phenoxybenzene-4,4'-disulphonyl chloride.

5. Composition according to claim 3, wherein the initiator is a monomeric multifunctional initiator and comprises an alkyl dihalide or sulphonyl halide, or is a polymer containing one or more radically transferable groups present at the chain ends and/or pendent to the main chain and distributed along its length.

6. Composition according to any preceding claim, wherein M is Fe[II], Fe[III], Co[II], Co[III], Cr[II], Cr[III], Mn[II], Mn[III], Mn[IV], V[II], V[III] or V[IV].

7. Composition according to any preceding claim, wherein R⁵ and R⁷ are independently selected from phenyl, 1-naphthyl, 2-naphthyl, 2-methylphenyl, 2- ethylphenyl, 2,6-diisopropylphenyl, 2,3-diisopropylphenyl, 2,4-diisopropylphenyl, 2,6-di-n-butylphenyl, 2,6-dimethylphenyl, 2,3-dimethylphenyl, 2,4-dimethylphenyl, 2-t- butylphenyl, 2,6-diphenylphenyl, 2,4,6-trimethylphenyl, 2,6-trifluoromethylphenyl, 4- bromo-2,6-dimethylphenyl, 3,5-dichloro2,6-diethylphenyl, 2,6,bis(2,6- dimethylphenyl)phenyl, cyclohexyl and pyridinyl.

8. Composition according to any preceding claim, wherein R⁵ is a group having the formula -NR²⁹R³⁰ and R⁷ is a group having the formula -NR³¹R³², wherein R²⁹ to R³² are independently selected from hydrogen, halogen, hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl or substituted heterohydrocarbyl; when any two or more of R¹ to R⁴, R⁶ and R²⁹ to R³² are hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl or substituted heterohydrocarbyl, said two or more can be linked to form one or more cyclic substituents.

9. Composition according to any preceding claim, wherein the compound of the formula L_pM^[m](Q) comprises:

2,6-di (l-[N-(2-methylphenyl) imino] isobutyl} pyridine iron dichloride, 2,6-bis-[(2,6-diisopropylphenylimino)methyl]pyridine iron(II) acetylacetonate hexafluoroantimonate,

2,6-diacetylpyridinebis (2,6-diisopropylanil) manganese dichloride, 2,6-diacetylpyridinebis (2, 4,6-trimethyl anil) chromium dichloride, 2,6-diacetylpyridinebis (2,6-diisopropylanil) chromium dichloride, 2,6-diacetylpyridinebis (2,6-diisopropylanil) titanium trichloride, 2,6-diacetylpyridinebis (2,6-diisopropylanil) iron dichloride,

2,6-diacetylpyridinebis (2,6-diisopropylanil) vanadium trichloride, or

2,6-bis-[ 1 -(2,6-diisopropylphenylamido)ethyl]pyridine iron dichloride or their precursors.

10 Composition according to any preceding claim, wherein L is chloride or bromide.

11. Composition according to any preceding claim, which is supported on an inorganic or organic solid support.

12. Process for the polymerisation or copolymerisation of a radically polymerisable monomer, comprising contacting the monomer under polymerisation conditions with a catalyst composition as defined in any preceding claim.

13. Process according to claim 12, wherein the monomer comprises ethylene, propylene, 1-butene, isobutene, 1-hexene, 1-octene, 1 ,3-butadiene, isoprene, acrylic acid, acrylic anhydride; (meth)acrylic acid, maleic acid, maleic anhydride, vinyl sulphonic acid, itaconic acid, (meth)acrylamide, N-methyl (meth)acrylamide, N,N'dimethyl (meth)acrylamide, vinyl chloride; (meth)acrylonitrile; methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, isobornyl acrylate, 2-hydroxy ethyl acrylate, 2-chloro ethyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate, 2-hydroxy ethyl methacrylate, 2-chloro ethyl methacrylate; vinyl acetate, vinyl propionate, vinyl butyrate; vinyl pyrrolidone, ethylvinyl ketone, butylvinyl ketone; vinyl substituted phenyls, vinyl substituted naphthyls, vinyl pyridine, N-amino ethyl acrylamide, N- aminoethyl acrylate, isoprene.

14. Process according to claim 13, wherein the the monomer is a vinyl substituted phenyl or naphthyl, optionally substituted with Cι-C₆ alkyl either at the alpha-carbon atom or on the aryl ring; and is preferably styrene or 1 ,4-divinyl benzene.

15. Process according to any one of claims 12 to 14, wherein the monomer is polymerised with a natural or synthetic rubber or combination thereof such that the resulting polymeric product comprises a polymer or copolymer having rubber grafted thereon, wherein the rubber comprises 1 ,4-polyisoprene, a natural rubber derived from the Hevea brasiliensis tree and quayule bush, polybutadiene rubber, polyisoprene rubber, styrene-butadiene rubber, nitrile rubber, neoprene rubber, polysulphide rubber, polyacrylate rubber, epichlorohydrin rubber, fiuoroelastomer, chlorosulphonated polyethylene rubber, polyurethane, or a thermoplastic rubber.

16. Use of a composition as defined in any of claims 1 to 1 1 as a polymerisation catalyst for radically polymerisable monomers.